Looking at a pals ice maker. Not looked at any this type before: it’s a GL193-2

Its forms ice in the tray but it doesn’t drop...so the ice block just continues to build up. I witnessed a ‘defrost’ cycle. The hot gas valve opens and begins to defrost the coil but didn’t stay on for long enough to drop the ice.

I’m assuming the the probe on the evap should tell the controller when to stop the defrost cycle? So I figure it’s the probe that’s the problem.

Any other ideas or common issues like this?